Mining machine head



July 31, 1951 c. E. COMPTON MINING MACHINE. HEAD Original Filed April19, 1950 3 Sheets-Sheet 1 INVENTOR CHARLES E. COMPTON July 31; 1951 c.E. COMPTON MINING MACHINE HEAD Original Filed April 19, 1950 5Sheets-Sheet 2 INVENTOR C HARLES E. COMPTON y 31, 1951 c. E. COMPTON2,562,841

MINING MACHINE HEAD Original Filed April 19, 1950 3 Sheets Sheet 5 JINVENTOR Patented July 31, 1951 MINING MACHINE HEAD Charles E. Compton,Shinnston, W. Va.

Continuation of application Serial No. April 19, 1950. This applicationJuly Serial No. 178,206

I 12 Claim.

This invention relates to mining machine heads, especially heads whichare advanceable into a working face or body of material to removematerial therefrom. This application is a continuation of my copendingapplication Serial No. 156,867, filed April 19, 1950, which in turn isin part a continuation of my copending application Serial No. 104,445,filed July 13, 1949, both applications now being abandoned.

The invention is concerned with mining or tunneling, depending uponwhether the purpose is to recover the removed material or to form atunnel. I use the word "mining herein as a word of broad definitioncomprehending removal of material whether the purpose is to recover thematerial or to form a tunnel.

Various types of mining machines have been proposed which are adapted tobe advanced toward a working face and which have heads designed to enterthe face and remove material therefrom, one use of such machines is inthe mining of coal although they may be otherwise used. For purposes ofexplanation and illustration I shall describe my invention in connectionwith the mining of coal.

Machines of the type above referred to which have heretofore beenproposed have not been fully satisfactory for the mining of coal.Generally they have had one or both of two disadvantages. A primarydisadvantage has been the breaking up of the coal into undesirably smallpieces. Another disadvantage has been the complexity of the machine andthe consequent high cost per ton of mining with it. Many machinesdesigned for the mining of coal have had both of the disadvantagesmentioned. The problem is one of long standing.

I provide a mining machine head which may be applied to any suitablemachine for rotating the head and advancing it into a face, which headis of rugged, simple and foolproof construction yet at the same timeremoves coal without breaking it up into undesirably small pieces anddelivers the coal with unprecedented economy. My head preferablycomprises a rotatable and advanceable cutter element having a materialpassage therethrough extending generally parallel to the axis ofrotation and having periphery cutting means mounted thereon at theforward end thereof disposed to cut a generally cylindrical kerf in abody of material upon rotation and advancement of the cutter element. Mycutter element may take the form of a hollow cylinder open at both endshaving periphery cutting means at its forward end which is adapted 2 toenter a face and sever therefrom a generally cylindrical mass which lieswithin the cylinder. Such a cylinder is not in itself new.

I combine with the cutter element other elements so that the combinationbrings. about a basically new operation. I provide means for movingrearwardly within the cutter element the material of the generallycylindrical mass (e. g., coal) at a speed such as to prevent clogging inthe cutting zone and without breaking up the material into small pieces.To most effectively accomplish that result the means for moving thematerial rearwardly within the cutter element, here for exampleconsidered as being in the form of a hollow cylinder as above described,should at least the portion thereof disposed at the rear or delivery endof the cylinder have a diameter substantially equal to the insidediameter of the cylinder. The cylinder may have a diameter of the orderof live or six feet, and with such a head I can regularly recover fromthe Pittsburgh seam in the west Virginia fields lumps of coal weighingto 300 pounds.

I provide as a part of the head a ribbed breaker which is preferably ofreduced diameter at its forward end or nose. The breaker has outwardlyprojecting rib means forming a generally spiral conveyor of relativelycoarse pitch extending rearwardiy and circumferentially and in operationof the head performs two distinct functions. The nose of the breakerenters the material being mined and cooperates with the cylinder incracking the material without breaking it up into small pieces. As thehead rotates and advances the breaker also acts as a conveyor, pushingthe fractured coal rearwardly within and finally out of the cylinder.Adjacent convolutions of the conveyor are spaced apart to provide spacetherebetween of materially greater crosssectional area than the ribmeans.

The breaker is preferably coaxial with the cutter element and connectedtherewith and preferably has inner cutting means mounted on the forwardend thereof. The breaker is preferably small enough at its forward endto enter the opening formed by the inner cutting means but wider thanthat opening at its rearward end. The breaker at a zone notsubstantially in advance of the periphery cutting means is preferably ofa width approximating that of the inner cutting means. The nose of thebreaker is preferably within the head and may be behind the forward endof the cylinder when the cutter element is in the form of a hollowcylinder. The breaker is desirably within and connected with thecylinder coaxial with the cylinder. It is normally entirely within thecylinder. In a head of the size above mentioned the nose of the screwmay follow the forward end of the cylinder by perhaps 12 to 18 inches.The breaker enters the opening formed by the inner cutting means andcauses the material to crack along irregular although somewhat radiallines outwardly toward the inner surface of the cylinder. At the sametime the rotating and advancing breaker works its way into the fracturedmaterial and propels it rearwardly without breaking it up into smallpieces. The forward extremity of the breaker should be behind theforward ends of the cutting means at the forward end of the cylinder.The inner cutting means may be behind the periphery cutting means or insubstantially the same transverse plane therewith or on occasionsomewhat in front of the periphery cutting means.

Other details, objects and advantages of the invention will becomeapparent as the following description of certain present preferredembodiments thereof proceeds.

In the accompanying drawings I have shown certain present preferredembodiments of the invention in which Figure 1 is a perspective view ofa mining machine head;

Figure 2 is a front view of the head shown in Figure 1;

Figure 3 is a view similar to Figure 1 of a different and presentlypreferred form of mining machine head;

Figure 4 is a view similar to Figure 2 of the head shown in Figure 3;

Figure 5 is an axial cross-sectional view of the head shown in Figures 1and 2 but with the inner cutting means and breaker; shown in elevation;and

Figure 6 is an axial crosssectional view of the head shown in Figures 3and 4 but with the inner cutting means and breaker shown in elevation.

Referring now more particularly to Figures 1, 2 and 5, I provide a shaftI mounted for rotation and advancement. The means for rotating andadvancing the shaft may be any suitable means for the purpose as knownin the art and may be connected with the shaft adjacent its rear endwhich is not shown in Figure l but is to the right of the portion of theshaft which appears in that figure. Since the invention of the presentapplication is concerned only with the head and not with the structureof the machine and since machines fcr advancing and rotating heads intoworking faces are old and known to those skilled in the art it isunnecessary to show any specific means for advancing and rotating thehead. Those skilled in the art will understand that the head is suitablysupported and aimed at the face to be penetrated.

The shaft 2 is preferably of substantial diameter, perhaps 12 to 18inches, and may be in the form of a hollow pipe. Applied to the shaft 2,as, for example, by welding, is a screw designated generally byreference numeral 3 and having a rear portion 4 of relatively greatdiameter and a tapered nose portion 5. The front end of the shaft 2 maybe tapered toward a point as shown at B, the tapered nose portion 5 ofthe screw 3 being an'outwardly projecting rid disposed about the reducedshaft end. The tapered shaft end I and the rib 5 form a breaker. Acutting tool I,

hereinafter called the inner cutting means, is

applied to the nose of the shaft and screw, 1. e., to the front end ofthe breaker, the shaft, screw and cutting tool all being coaxial.

Disposed about the portions 5 and ll of the screw and the shaft and thetool I is a cutter element 8 having a material passage therethroughextending generally parallel to the axis of the shaft 2, which is theaxis of rotation and advancement of the cutter element 8, and havingperiphery cutting means in the form of cutters 9 and Ill mounted thereonat the forward end thereof disposed to cut a generally cylindrical kerfin a body of material upon rotation and advancement of the cutterelement. The cutter element 8 shown takes the form of a cylinderarranged coaxial with the shaft and screw. The cylinder may have adiameter of perhaps five or six feet and may have a length of perhapssix feet. The internal diameter of the cylinder 8 is preferablysubstantially equal to the diameter of the portion 4 of the screw and itis ordinarily preferable to fasten the screw to the cylinder; in

Figures 1, 2 and 5 the periphery of the screw is welded to the inside Ofthe cylinder throughout a suiflcient length of the screw to insure apermanent connection under operating conditions; thus the shaft, screwand cylinder are all coaxial and unitary. In any event it is desirablethat at least a portion of the screw have a diameter approximating theinside diameter of the cylinder which carries the cutting means wherebyto obtain maximum material cutting and removing efllciency.

The periphery cutting means or cutters 9 and III are mounted on thecylinder at its forward end and project from the forward end of thecylinder as shown in Figures 1, 2 and 5 and additional cutters H arefastened to the inside of the cylinder and lie substantially against itsinside surface somewhat rearwardly of its forward end. A spiralprojection I2 is provided on the outside of the cylinder for conveyingrearwardly along the outside of the cylinder as the cylinder rotates andadvances small particles cut from the face which do not find their wayto the inside of the cylinder. Such spiral projection obviates thecollecting and jamming of small cuttings against the cylinder and theconsequent tendency to bind the cylinder. By removing such smallcuttings or particles the cylinder works relatively freely and the powerrequired for its operation is much less than were the spiral projectionnot employed. The spiral projection I! may be a double lead spiral, i.e., it may consist of two spirals starting from the forward end of thecylinder apart and having the same pitch.

The cutters 9, HI and II have cutting faces which cut into the coal asthe cylinder rotates and advances. The cutters may have a radialdimension substantially equal to the thickness of the material of thecylinder and the cutters 9 and Ill may project from the cylinder wall inaxial alignment therewith, although I prefer to have some of thecutters, i. e., the cutters 9, projecting in the radial direction fromthe cylinder so that their radially outside surfaces lie approximatelyin a cylinder defined by the radially outside surface of the outsidespiral projection II. For example, alternate cutters 9 and Illcircumferentially of the cylinder may have their radially outsidesurfaces (a) approximately in the cylinder defined by the outsidesurface of the rotatable and advanceable hollow cylinder and (b)projecting in the radial direction from the rotatable and advanceablehollow cylinder so that their radially outside surfaces lieapproximately in a cylinder defined by the radially outside surface ofthe outside spiral projection II. The cutters II are optional and may beused or not as desired. When they are used they somewhat increase thecutting efficiency but may result in slightly reducing the size of thelumps of coal recovered.

The tapered nose portion 5 of the screw I forms a spiral rib or conveyorof reduced diameter relatively to the portion 4 which recreases to thefull inside diameter of the cylinder and the full diameter of theposition 4 at a portion of the screw which lies within the cylinder andthe pitch of the rib 5 also preferably increases so that its conveyingefficiency increases rapidly from its nose rearwardly, causing the coalto be somewhat accelerated in its rearward movement. This obviatesclogging in the cutting zone, in turn considerably contributing to therecovery of large lumps as above mentioned. The coal is not crowded upand ground together but has free space into which to move in beingpropelled to the rear by the screw. The screw propels the coal out ofthe rear end of the cylinder and if the cylinder is driven into the facea distance greater than its length the screw projecting rearwardly fromthe cylinder cooperates with the cylindrical bore formed in the face todeliver the coal rearwardly therethrough.

Thus the breaker performs a twofold function of entering and crackingthe coal at is reduced forward end and conveying the coal rearwardly atthe portion thereof behind the forward end.

The screw acts continuously on the coal so that the coal is cracked andpushed rearwardly with great force but without great violence. Thecracking of the coal into large lumps is contributed to by the fact thatthe breaker consisting of the tapered forward end 6 of the shaft 2 andthe spiral rib 5 is at a zone not sub stantially in advance of the nosesof the cutters 9 and ill of a width approximately that of the innercutter 1 so that the breaker will not act on the coal substantially inadvance of the periphery cutting means. In the form of Figures 1, 2 and5 the periphery cutters 9 and Ill lead the breaker in its advance intothe face so when the breaker acts on the coal that coal has already beensevered from the face by the periphery cutting means; the nose of thebreaker is shown as being disposed rearwardly of the forward end of thecylinder 8 a distance of the order of 12 to 18 inches.

The breaker rib 5 forms a generally spiral conveyor of relatively coarsepitch extending rearwardly and circumferentially. Adjacent convolutionsof the conveyor are spaced apart to provide passage space therebetweenof materially greater cross-sectional area than the rib. The passagespace in the breaker preferably, as shown in Figures 1 and 5, increasesin cross-sectional area in the direction from the forward end toward therearward end of the breaker. This is accomplished by divergence ofadjacent convolutions of the rib means 5 from the forward end toward therearward end of the breaker.

After the forward end of the cylinder has penetrated the face to someextent the tool I cuts into the mass of coal severed from the face andlying within the cylinder. Following the tool 1 comes the reduced shaftend 6 and the portion 5 of the screw 3 which enters the coal and cracksit generally radially outwardly to the inner surface of the cylinder andimmediately commences exerting rearward pressure on it. As the headturns more and more rearward pressure is exerted on the lumps of coal bythe screw of increasing size, the rate of speed of the head into theface preferably being relatively slow as compared with the rate ofrearward delivery of the coal by the screw. Hence the coal is quicklyremoved from the zone of the front end of the screw and by the portion 3of the screw is delivered rearwardly out of the cylinder 8.

If the cylinder should be advanced into the face a distance greater thanits own length the portion I of the screw which extends rearwardly fromthe cylinder will cooperate with the inner surface of the bore formed inthe face to deliver the coal outwardly therefrom. The thu's deliveredcoal is removed by any suitable means.

Instead of having the forward extremity of the screw conveyor tapered orreduced to smaller diameter I may make the screw conveyor of uniformdiameter from end to end but with the front end thereof behind thebreaking tool. In such case it is desirable to provide on the shaftbetween the inner cutting means and the screw conveyor means breakingmaterial and propelling it rearwardly. Such a structure is shown inFigures 3, 4 and 6 which depict a mining machine head which is presentlypreferred because of its strength and ruggedness and because of itsrelatively low cost of manufacture. Parts in Figures 3, 4 and 6 whichare the same as parts in Figures 1, 2 and 5 are designated by the samereference numerals as are applied to those parts in Figures 1, 2 and 5but with a prime affixed.

The form of Figures 3, 4 and 6 differs from the form of Figures 1, 2 and5 primarily in that in the form of Figures 3, 4 and 6 the screw 3' doesnot have a tapered nose portion corresponding to the tapered noseportion 5 of the screw 3. The screw 3' is of the same diameter from endto end, terminating at its front end in an edge II. The edge I3 isdisposed at approximately the rear end of the tapered portion 6' of theshaft 2'. A cutting tool I is carried by the shaft 2' at its forward endas in the form of Figures 1, 2 and 5 but the front ends of the cuttersof the tool I are disposed closer to the front end of the mining machinehead in the form of Figures 3, 4 and 6 than in the form of Figures 1, 2and 5. I find it desirable to have the front end of the tool Irelatively close to the front end of the mining machine head althoughthe position of the tool is subject to some variation. In Figure 6 thefront end of the cutting tool 1' is somewhat in advance of the frontends of the cutters 9', III and II.

In Figures 3, 4 and 6 I show curved or spiral ribs H welded to thetapered portion 8' of the shaft 2', some of the ribs ll commencing closeto the cutting tool I and others commencing farther back on the taperedportion 6'. The ribs ll terminate at approximately the transverse planeof the edge H at the front end of the screw 3'. The curvature of theribs is consonant with the direction of advance of the screw so that theribs in effect form a forward extension of the screw. The ribs I! serveto propel rearwardly material broken up by the breaking tool comprisingthe tapered shaft portion 8 having the ribs thereon and cooperate withthe screw 3 to deliver the broken-up material away from the face. Thusthe tapered nose portion Ii of the shaft 2' with the ribs ll thereonforms in effect a reduced front end on the screw 3. The ribs preferablydiverge in the direction from the forward end toward the rearward end ofthe breaker so that the passage space therebetween increases incross-sectional area in the direction from the forward end toward therearward end of the breaker. It is much cheaper to weld the ribs ll ontothe shaft than it is to form the portion of reduced diameter at thefront end of the screw I in the form of Figures 1, 2 and 5; also thedanger of deformation or breakage of the reduced front end of the screwis eliminated. The breaker of Figures 3, 4 and 6 has otherwise the samestructural and operating characteristics as the breaker of Figures 1, 2and 5 and functions in the same manner. The above description of thebreaker of Figures 1, z and 5 and its operation applies generally to thebreaker of Figures 3, 4 and 6 and its operation.

In Figures 3, 4 and 6 there is shown in addition to the outside spiralprojection I! a series of inside spiral projections it which lead in thesame direction as the outside spiral projection l2 and aid in projectingor advancing rearwardly material severed from the face by the cutters 9'and HI and broken up by the tool I. The inside spiral projections i5extend from approximately the front edge of the cylinder 8' rearwardlyfor a short distance although they may be extended rearwardly all theway to the front end of the screw 3' if desired.

The cutters 9', III and H of Figures 3, 4 and 6 correspond respectivelywith the cutters 9, III and of Figures 1, 2 and 5. In Figures 3, 4 and 6the cutters II are arranged in the same transverse plane as the cutters9' and it instead of being disposed in a separate transverse plane tothe rear of the plane of the other cutters as in the form of Figures 1,2 and 5. The inside outters li' may have their radially inside surfaceslying approximately in a cylinder defined by the radially insidesurfaces of the inside spiral projections it.

In both the form of head shown in Figures 1, 2 and 5 and the form ofhead shown in Figures 3, 4 and 6 there is embodied a rotatable andadvanceable cutter element having a material passage therethroughextending generally parallel to the axis of rotation and havingperiphery cutting means mounted thereon at the forward end thereofdisposed to cut a generally cylindrical kerf in a body of material uponrotation and advancement of the cutter element, the cutter elementtaking the form of a cylinder open at both ends and carrying adjacentits forward end periphery cutting means for cutting into a body ofmaterial upon rotation and advancement of the cylinder; there is abreaker coaxial with the cutter element within and connected with thecylinder, the breaker at a zone not substantially in advance of theperiphery cutting means being of a width approximating that of innercutting means mounted on its forward end and specifically having itsforward end rearwardly of the periphery cutting means; the breaker issmall enough at its forward end to enter the opening formed by the innercutting means but is wider than that opening at its rearward end; thebreaker has outwardly projecting rib means forming a generally spiralconveyor of relatively coarse pitch extending rearwardly andcircumferentially adjacent convolutions of the conveyor are spaced apartto provide passage space therebetween of materially greatercross-sectional area than the rib means; the conveyor is pitched and thepassage space is proportioned to the size of the inner cutting means sothat the passage space accommodates and the conveyor conveys rearwardlysubstantially all of the cuttings formed by the inner cutting meanswhich enter the passage space and the conveyor engages and propelsrearwardly lumps of the material; the breaker comprises a tapered corehaving conveying rib means on the exterior thereof; the passage spacebetween adjacent convolutions of the conveyor increases incrosssectional area in the direction from the forward end toward therearward end of the breaker; the conveying rib means diverge in thedirection from the forward end toward the rearward end of the breaker;there is provided a rotatable spiral conveyor extending rearwardly fromthe cylinder, the annular space within the cylinder about and rearwardlyof the breaker being completely open to deliver material unimpeded fromwithin the cylinder to the last mentioned spiral conveyor; and the lastmentioned spiral conveyor is connected with the cylinder and isrotatable and advanceable therewith and extends rearwardly therefrom,the cylinder being mounted solely on the periphery of the last mentionedspiral conveyor.

While I have shown and described certain present preferred embodimentsof the invention it is to be distinctly understood that the invention isnot limited thereto but may be otherwise variously embodied within thescope of the following claims.

I claim:

1. A mining machine head comprising a rotatable and advanceable cylinderopen at both ends, periphery cutting means carried by the cylinderadjacent the forward end thereof for cutting into a body of materialupon rotation and advancement of the cylinder, a breaker coaxial withthe cylinder within and connected with the cylinder having its forwardend rearwardly of the periphery cutting means, and inner cutting meansmounted on the forward end of the breaker, the breaker being smallenough at its forward end to enter the opening formed by the innercutting means but being wider than that opening at its rearward end, thebreaker having outwardly projecting rib means forming a generally spiralconveyor of relatively coarse pitch extending rearwardly andcircumferentially, adjacent convolutlons of the conveyor being spacedapart to provide passage space therebetween of materially greatercross-sectional area than the rib means, the conveyor being pitched andthe passage space being proportioned to the size of the inner cuttingmeans so that the e space accommodates and the conveyor conveysrearwardly substantially all of the cuttings formed by the inner cuttingmeans which enter the passage space and the conveyor engages and propelsrearwardly lumps of the material.

2. A mining machine head comprising a rotatable and advanceable cylinderopen at both ends, periphery cutting means carried by the cylinderadjacent the forward end thereof for cutting into a body of materialupon rotation and advancement of the cylinder, a breaker coaxial withthe cylinder within and connected with the cylinder having its forwardend rearwardly of the periphery cutting means, and inner cutting meansmounted on the forward end of the breaker, the breaker being smallenough at its forward end to enter the opening formed by the innercutting means but being wider than that awash opening at its rearwardend and comprising a tapered core having on the exterior thereofoutwardly projecting rib means forming a generally spiral conveyor ofrelatively coarse pitch extending rearwardly and circumferentially,adjacent convolutlons of the conveyor being spaced apart to providepassage space therebetween of materially greater cross-sectional areathan the rib means, the conveyor being pitched and the passage spacebeing proportioned to the size of the inner cutting means so that thepassage space accommodates and the conveyor conveys rearwardlysubstantially all of the cuttings formed by the inner cutting meanswhich enter the passage space and the conveyor engages and propelsrearwardly lumps of the material.

3. A mining machine head comprising a rotatable and advanceable cylinderopen at both ends, periphery cutting means carried by the cylinderadjacent the forward end thereof for cutting into a body of materialupon rotation and advancement of the cylinder, a breaker coaxial withthe cylinder within and connected with the cylinder having its forwardend rearwardly of the periphery cutting means, and inner cutting meansmounted on the forward end of the breaker, the breaker being smallenough at its forward end to enter the opening formed by the innercutting means but being wider than that opening at its rearward end, thebreaker having outwardly projecting rib means forming a generally spiralconveyor of relatively coarse pitch extending rearwardly andcircumferentially, adjacent convolutions of the conveyor being spacedapart to provide passage space therebetween of materially greatercross-sectional area than the rib means, the passage space increasing incrosssectional area in the direction from the forward end toward therearward end of the breaker.

4. A mining machine head comprising a rotatable and advanceable cylinderopen at both ends, periphery cutting means carried by the cylinderadjacent the forward end thereof for cutting into a body of materialupon rotation and advancement of the cylinder, a breaker coaxial withthe cylinder within and connected with the cylinder, and inner cuttingmeans mounted on the forward end of the breaker, the inner cutting meanshaving its forward end rearwardly of the periphery cutting means, thebreaker being small enough at its forward end to enter the openingformed by the inner cutting means but being wider than that opening atits rearward end, the breaker having outwardly projecting rib meansforming a generally spiral conveyor of relatively coarse pitch extendingrearwardly and circumferentially, adjacent convolutions of the conveyorbeing spaced apart to provide passage space therebetween of materiallygreater cross-sectional area than the rib means, the conveyor beingpitched and the passage space being proportioned to the size of theinner cutting means so that the passage space accommodates and theconveyor conveys rearwardly substantially all of the cuttings formed bythe inner cutting means which enter the passage space and the conveyorengages and propels rearwardly lumps of the mate- 5. A mining machinehead comprising a rotatable and advanceable cylinder open at both ends,periphery cutting means carried by the cylinder adjacent the forward endthereof for cutting into a body of material upon rotation andadvancement of the cylinder, a breaker coaxial with the cylinder withinand connected with the cylinder having its forward end rearwardly of theperiphery cutting means, inner cutting mea mounted on the forward end ofthe breaker, e breaker being small enough at its forward end to enterthe opening formed by the inner cutting means but being wider than thatopening at its rearward end, the breaker having outwardly projecting ribmeans forming a generally spiral conveyor of relatively coarse pitchextending rearwardly and circumferentially, adjacent convolutions of theconveyor being spaced apart to provide passage space therebetween ofmaterially greater cross-sectional area than the rib means, the conveyorbeing pitched to engage and propel rearwardly lumps of the material, anda rotatable spiral conveyor extending rearwardly from the cylinder, theannular space within the cylinder about and rearwardly of the breakerbeing completely open to deliver material unimpeded from within thecylinder to the last mentioned spiral conveyor.

6. A mining machine head comprising a rotatable and advanceable cylinderopen at both ends, periphery cutting means carried by the cylinderadjacent the forward end thereof for cutting into a body of materialupon rotation and advancement of the cylinder, a breaker coaxial withthe cylinder within and connected with the cylinder having its forwardend rearwardly of the periphery cutting means, inner cutting meansmounted on the forward end of the breaker, the breaker being smallenough at its forward end to enter the opening formed by the innercutting means but being wider than that opening at its rearward end, thebreaker having outwardly projecting rib means forming a generally spiralconveyor of relatively coarse pitch extending rearwardly andcircumferentially, adjacent convolutions of the conveyor being spacedapart to provide passage space therebetween of materially greatercross-sectional area than the rib means, and a spiral conveyor connectedwith the cylinder, rotatable and advanceable therewith and extendingrearwardly therefrom, the cylinder being mounted solely on the peripheryof the last mentioned spiral conveyor.

7. A mining machine head comprising a rotatable and advanceable cylinderopen at both ends, periphery cutting means carried by the cylinderadjacent the forward end thereof for cutting into a body of materialupon rotation and advancement of the cylinder, a breaker coaxial withthe cylinder within and connected with the cylinder having its forwardend rearwardly of the periphery cutting means, and inner cutting meansmounted on the forward end of the breaker, the breaker being smallenough at its forward end to enter the opening formed by the innercutting means but being wider than that opening at its rearward end, thebreaker having outwardly projecting rib means forming a generally spiralconveyor of relatively coarse pitch'extending rearwardly andcircumferentially, adjacent convolutions of the conveyor being spacedapart to provide passage space, the rib means diverging in the directionfrom the forward end toward the rearward end of the breaker.

8. A mining machine head comprising a rotat-- able and advanceablecutter element having a material passage therethrough extendinggenerally parallel to the axis of rotation and having periphery cuttingmeans mounted thereon at the forward end thereof disposed to cut agenerally cylindrical kerf in a body of material upon rotation andadvancement of the cutter element,

asaaan a breaker coaxial with the cutpr element and connected therewith,and inner cutting means mounted onihe forward end of the breaker, thebreaker bll'imall enough at its forward end to enter the opening formedby the inner cutting means but being wider than that opening at its"rearward end, the breaker at a zone not sube' tantially in advance ofthe periphery cutting means being of a width approximating that of theinner cutting means, the breaker having outwardly projecting rib meansforming a generally spiral conveyor of relatively coarse pitch extendingrearwardly and circumferentially, adjacent convolutions of the conveyorbeing spaced apart to provide passage space therebetween of materiallygreater cross-sectional area than the rib means, the conveyor beingpitched and the passage space being proportioned to the size of theinner cutting means so that the passage space accommodates and theconveyor conveys rearwardly substantially all of the cuttings formed bythe inner cutting means which enter the passage space and the conveyorengages and propels rearwardly lumps of the material.

9. A mining machine head comprising a rotatable and advanceable cutterelement having a material passage therethrough extending generallyparallel to the axis of rotation and having periphery cutting meansmounted thereon at the forward end thereof disposed to cut a generallycylindrical kerf in a body of material upon rotation and advancement ofthe cutter element, a breaker coaxial with the cutter element andconnected therewith and having its forward end rearwardly of theperiphery cutting means, and inner cutting means mounted on the forwardend of the breaker, the breaker being small enough at its forward end toenter the opening formed by the inner cuttin means but being wider thanthat opening at its rearward end, the breaker having outwardlyprojecting rib means forming a generally spiral conveyor of relativelycoarse pitch extending rearwardly and circumferentially, adjacentconvolutions of the conveyor being spaced apart to provide passage spacetherebetween of materially greater cross-sectional area than the ribmeans, the conveyor being pitched and the passage space beingproportioned to the size of the inner cuttin means so that the passagespace accommodates and the conveyor conveys rearwardly substantially allof the cuttings formed by the inner cutting means which enter thepassage space and the conveyor engages and propels rearwardly lumps ofthe material.

10. A mining machine head comprising a rotatable and advanceablecylinder open at both ends, periphery cutting means carried by thecylinder adjacent the forward end thereof for cutting into a body ofmaterial upon rotation and advancement of the cylinder, 9, breakercoaxial with the cylinder within and connected with the cylinder, andinner cutting means mounted on the forward end of the breaker, thebreaker being small enough at its forward end to enter the openingformed by the inner cutting means but being wider than that opening atits rearward end, the breaker at a zone not substantially in advance ofthe periphery cutting means being of a width approximating that of theinner cutting means, the breaker having outwardly projecting rib meansforming a generally spiral conveyor of relatively coarse pitch extendingrearwardly and circumferentially, adjacent convolutions of the conveyorbeing spaced apart to provide passage space therebetween of materiallygreater crosssectional area than the rib means, the conveyor beingpitched and the passage space being proportioned to the size of theinner cutting mean so that the passage space accommodates and theconveyor conveys rearwardly substantially all of the cuttings formed bythe inner cutting means which enter the passage space and the conveyorengages and propels rearwardly lumps of the material.

ii. A mining machine head comprising a rotatable and advanceable cutterelement having a material passage therethrough extending generallyparallel to the axis of rotation and having periphery cutting meansmounted thereon at the forward end thereof disposed to cut a generallycylindrical kerf in a body of material upon rotation and advancement ofthe cutter element, a breaker coaxial with the cutter element andconnected therewith, and inner cutting means mounted on the forward endof the breaker, the breaker being small enough at its forward end toenter the opening formed by the inner cutting means but being wider thanthat opening at its rearward end, the breaker at a. zone notsubstantially in advance of the periphery cutting means being of a widthapproximating that of the inner cutting means, the breaker havingoutwardly projecting rib means forming a enerally spiral conveyor ofrelatively coarse pitch extending rearwardly and circumferentiaily,adjacent convolutions of the conveyor being spaced apart to providepassage space therebetween of materially greater cross-sectional areathan the rib means, the conveyor being pitched and the passage spacebeing proportioned to the size of the inner cutting means so that thepassage space accommodates and the conveyor conveys rearwardlysubstantially all of the cuttings formed by the inner cutting meanswhich enter the passage space and the conveyor engages and propelsrearwardly lumps of the material, the passage space increasing incross-sectional area in the direction from the forward end toward therearward and of the breaker.

12. A mining machine head comprising a retatable and advanceable shaft,a spiral conveyor disposed about the shaft and mounted thereon forrotating and advancing movement with the shaft and adapted to conveyrearwardly about the shaft material entering the forward end of theconveyor, a cylinder open at both ends substantialy coaxial with theshaft and mounted upon the spiral conveyor for rotating and advancingmovement with the shaft and spiral conveyor, periphery cutting meanscarried by the cylinder adjacent the forward end thereof for cuttinginto a body of material upon rotation and advancement of the cylinder, abreaker on the forward end of the shaft substantially coaxial with thecylinder, disposed within the cylinder and having its forward endrear-wardly of the periphery cutting means, and inner cutting meansmounted on the forward end of the breaker, the breaker being smallenough at its forward end to enter the opening formed by the innercutting means but being wider than that opening at its rearward end, thebreaker having outwardly projecting rib means formin a generally spiralconveyor portion of relatively coarse pitch extending rearwardly andcircumferentially substantially to the first mentioned spiral conveyor,adjacent convolutions of said spiral conveyor portion being spaced apartto provide passage space therebetween of materially greatercrosssectional area than the rib means. the spiral conveyor portionbeing pitched and the passage space being proportioned to the size ofthe inner cutting means so that the passage space accommodates and thespiral conveyor portion conveys rearwardly to the first mentioned spiralconveyor substantially all of the cuttings formed by the inner cuttingmeans which enter the passage space and the spiral conveyor portionengages and propels rearwardly lumps of the materiaL CHARLES E. COMPTON.

REFERENCES CITED The following references are of record in the file ofthis patent:

Number Number 14 UNITED STATES PATENTS Name Date Woiford Jan. 13, 1891Tonge. Jr. Sept. 19, 1905 Walker July 2, 1918 Joy July 30, 1918 Joy Feb.13, 1923 Hansen b. Aug. 19, 1924 FOREIGN PATENTS Country Date GermanyMay 12, 1900

